System for dynamically allocating channels among base stations in a wireless communication system

ABSTRACT

A wireless communication system includes a plurality of wideband base stations and a cluster controller that dynamically controls channel allocations among the base stations. When a base station can not service a radio telephone terminal within its cell site, the base station polls the channels and sends a request for a channel to the controller, listing in the request the channels the station determines at the cell site to be inactive. The controller consults a load statistics table to determine if a first listed channel is free over the system. If so, the controller allocates the channel to the base station, if not the controller searches the table for a free channel. The controller may also include channel usage rates in the table. These rates indicate for a predetermined period of time for each base station the rate at which the base station assigns channels to the terminals and the number of channel in use simultaneously. The controller checks the channel usage rate associated with the base station to which the free channel is allocated to determine if the rate is below a predetermined maximum value. If so, the controller allocates the channel. Otherwise, the controller searches the table for a next free listed channel, and so forth. The controller may also preallocate channels to the base station based on expected use. To determine expected use, the controller accumulates the channel usage information over a number of predetermined periods of time and determines a pattern of use, if possible. The controller then, at appropriate times, i.e., when the pattern indicate changes in usage, preallocates channels from the base stations with low expected use to the base stations with high expected use.

This is a continuation of application Ser. No. 08/246,181, filed May 19,1994 which is now abandoned.

FIELD OF THE INVENTION

This invention relates generally to wireless communication systems, andmore particularly, to dynamic allocation of communication channels amongbase stations in wireless communication systems.

BACKGROUND

Wireless cellular communication Systems transmit information to and frommobile telephone units, or terminals, operating within their territory.Each of the systems communicates with these terminals over a number ofchannels within a specified frequency range assigned to the system by,for example, a government agency such as the Federal CommunicationsCommission.

Each system allocates the channels within its assigned range among aplurality of base stations, which are strategically positionedthroughout the system's territory. Each base station operates within apredetermined area, or cell site, and services the terminals located ortraveling in the site. To service a terminal, that is, to enable theterminal to participate in a call, the base station assigns to it one ofthe allocated channels. The base station also connects this channel,through one or more switches, to a land-based telephone line or toanother wireless channel, as appropriate, to complete the call.

Before the channels are allocated among the base stations, an extensivestudy is often performed to determine how best to allocate the channelsover the terrain covered by the system, to make channels availablethroughout the entire terrain with minimum interference. The study alsodetermines how to re-use channels, i.e. allocate respective channels tomore than one base station, to maximize channel availability. Thechannels are then permanently allocated to the respective base stationsin accordance with the study, and transceivers housed in each of thebase stations are tuned, respectively, to the appropriate channels.

The base stations can simultaneously service, on any given channel, upto a maximum number, n, of terminals. For example, a system operatingunder the IS-54B protocol and utilizing full encoding can simultaneouslyservice up to three (i.e., n=3) terminals per channel. As wirelesscommunication, and thus, terminals, become more and more popular, thedemand for channels increases. Accordingly, base stations servicingcertain high traffic areas may require additional channels.

Before an additional channel can be allocated to a base station,however, the possibility of interference with the channels ofneighboring base stations must be determined, an additional transceivermust be installed and tuned to the appropriate channel, and the basestation's switching circuitry must be updated to include the additionaltransceiver. Accordingly, adding a channel to a base station in such asystem is both costly and time consuming. These systems thus cannoteasily adapt to meet the increased demand.

Recently, personal communications services (PCS's) have been developedto handle communications within relatively small areas, for example,within a complex of buildings. PCS's typically include a number ofrelatively low-power base stations that service only terminals locatedwithin the complex. The PCS base stations, like the base stations of thehigher-powered wireless communications systems, are allocated a numberof channels over which to communicate with the terminals. As theterminals move throughout the complex, certain base stations mayexperience demands for channels that exceed their allocated capacity.

The PCS's are not generally under the control of the government agenciesthat assign the larger frequency ranges to the higher-powered wirelesscommunication systems. Thus a PCS may use frequencies, i.e., channels,that are already in use by a higher-powered base station in the samearea. Depending on the frequencies used by the PCS and the location ofthe PCS within the cell site associated with the higher-powered basestation, the communications of the two systems over certain channels mayinterfere with one another.

If such interference occurs, various channels must be re-allocated, ifpossible, or go unused, to remove from the affected base stations thechannels over which interference occurs. For example, certain channelsmay be re-allocated in the higher-powered system to base stations thatare located away from the PCS. Such a re-allocation of channels involvesat least the re-tuning of the transceivers in the affectedhigher-powered base stations. It may also require the re-tuning oftransceivers at a number of other base stations, should a change in thechannels allocated to these stations be required to avoid interferencewith the newly allocated channels. This procedure is both time consumingand costly. If re-allocation is not possible, certain channels may beunusable by the affected base stations, which may be any base station inthe PCS. This effectively reduces the allocated capacities of these basestations.

What is needed is a wireless communications system that can readilyadapt to changes in its operating environment, whether the changes areattributable to increased demand for channels, the installation of oneor more PCS's in the area, or both.

SUMMARY OF INVENTION

The invention is a system for dynamically allocating communicationchannels among a plurality, or "cluster," of wideband base stations. Thesystem includes a central cluster controller that allocates the channelsamong the base stations based on current demand for channels, i.e., atthe requests of the respective base stations; expected demand forchannels; or both. The wideband base stations each include a widebandtransceiver that is capable of operating simultaneously on any number ofthe channels within the frequency range assigned to the associatedservice provider. Each wideband base station can poll every channel todetermine signal activity, and thus, dynamically determine which of thechannels will potentially interfere with the operations of neighboringbase stations. Further, these transceivers can transmit essentiallysimultaneously over any or all of the channels, which enables them tooperate with newly allocated channels.

More specifically, the cluster controller maintains a load statisticstable that indicates for each channel at least the base stations towhich it is allocated and its current status in the system, i.e.,whether it is then assigned to a terminal or is then free. Theinformation on the current status of the channels is obtained directlyfrom the base stations. They each send contemporaneous notices to thecontroller, detailing channel assignments and channel releases.

In a first embodiment of the system, the base stations send requests foradditional channels to the cluster controller. Before sending a request,a base station surveys its environment by polling the channels in thesystem and determining which of these channels are "inactive," i.e.,have no detectable signals at that cell site. The station then sends tothe cluster controller as part of the request a list of one or more ofthe channels that it has determined are inactive.

In response to the request, the controller consults its load statisticstable and determines the current status of the first channel on thefist. If the channel is free, the controller reallocates it from thebase station to which it is currently allocated to the requesting basestation. To do this the controller sends a message to both basestations, informing them of the channel reallocation. These basestations then update their respective internal tables of allocatedchannels, and the controller updates its load statistics table.

The controller may also store in its load statistics table informationrelating to the rates at which each base station uses channels. Thisinformation includes for each base station the number of channelsassigned by the base station over a predetermined period of time and thenumber of these channels that are simultaneously in use over this timeperiod. From this accumulated information the controller determineschannel use rates for the base stations. If the channel use rate of abase station exceeds a predetermined maximum value, it indicates thatthe base station requires the channels currently allocated to it, tohandle current demand. Accordingly, the controller checks the channeluse rate associated with a free channel before re-allocating the channeland does not re-allocate the channel if the associated rate exceeds thepredetermined maximum value. The controller then re-enters the tablewith a next channel from the list and determines if this channel shouldbe re-allocated, and so forth.

In an alternative embodiment of the system, the controller accumulatesinformation relating to the channel usage of each of the base stationsover predetermined periods of time, for example, over days, hours, andso forth. Using this accumulated information, the controller determinespatterns of use. Then, based on these patterns the cluster controller,at its own initiative and at selected times, "preallocates" the channelsamong the base stations. At a designated time, the controller thusremoves channels from the base stations that are then expected to havelow demand and allocates these channels to base stations that are thenexpected to have high demand. By preallocating these channels, thecontroller enables the high-demand stations to handle their expectedincreased use without having to acquire the additional channelsone-by-one through a series of requests to the controller.

For example, the controller may determine that the base stations thatare located in a city have a high demand for channels during the weekand a low demand for channels on weekends; and the base stations locatedin the suburbs have a high demand for channels on the weekends and a lowdemand for channels during the week. At the start of the week, thecontroller preallocates more channels to the city base stations andfewer channels to the suburban base stations and at the start of theweekend does just the opposite.

If the controller accumulates and analyzes information based on thehours of the day, the controller may determine that particular basestations have high demand during specific hours, while other basestations have correspondingly low demand. The controller can thenpreallocate channels from the low-demand base stations to thehigh-demand base stations at the appropriate hours. For example, thecontroller may preallocate more channels during rush hours to the basestations on commuter routes and at the same time fewer channels to thebase stations on either end of these travel routes.

When the actual demand for channels exceeds the expected demand at aparticular base station, that base station surveys its environment andsends to the cluster controller a request for an additional channel. Thecontroller then consults its load statistics table to determine which ofthe channels on the list is currently both free and allocated to a basestation that is expected to have low demand. If one of the channelsmeets both criteria, the controller allocates it to the requesting basestation. Otherwise, the controller may leave the channel with the basestation to which it is currently allocated or may reallocate it to therequesting base station, depending on the priorities of the serviceprovider, as discussed below.

In either embodiment, the controller may re-use one of the listedchannels, by allocating the channel to the requesting base stationwithout removing it from the base station to which it is currentlyassigned. The controller need not determine if the re-use will causeinterference, however, since the requesting base station has alreadydetermined that it cannot detect signals transmitted over this channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings, in which:

FIG. 1 is a block diagram of a wireless communication system constructedin accordance with the current invention, the system including aplurality of wideband base stations and a cluster controller;

FIG. 2 is a functional block diagram of the cluster controller depictedin FIG. 1, constructed in accordance with a first embodiment of thecurrent invention;

FIGS. 3A and 3B together are a flow chart of the operations of thecluster controller depicted in FIG. 2 and the plurality of wideband basestations depicted in FIG. 1;

FIGS. 4A and 4B together are a flow chart of alternative operations ofthe cluster controller of FIG. 2;

FIG. 5 is a more detailed functional block diagram of the clustercontroller depicted in FIG. 1, constructed in accordance with a secondembodiment of the current invention;

FIG. 6 is a flow chart of the operations of the cluster controllerdepicted in FIG. 5 and the plurality of wideband base stations depictedin FIG. 1;

FIG. 7 is a functional block diagram of the cluster controller depictedin FIG. 1, constructed in accordance with a second embodiment of thecurrent invention;

FIG. 8 is a flow chart of the operations of the cluster controllerdepicted in FIG. 4 and the plurality of wideband base stations depictedin FIG. 1;

FIG. 9 is a flow chart of additional operations of the clustercontroller depicted in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a wireless communication system 10 includes acluster controller 12 that controls the allocation of channels among aplurality of wideband base stations 14. Each wideband base station 14operates over an associated cell site 16 and services terminals 18therein, by assigning to them, as needed, the channels then allocated tothe station.

Each of the wideband base stations 14 is capable of simultaneouslyutilizing any and all of channels available to the wirelesscommunication system 10. Currently, systems such as Advanced MobilePhone Systems are assigned frequency ranges of over 12 Mhz, whichinclude well over 400 channels. The communication system 10 similarlymay utilize many hundreds of channels.

The wideband base stations, which are discussed in more detail incopending patent application Ser. No. 08/224,754 entitled TransceiverApparatus Employing Wideband FFT Channelizer With Output Sample Timing,Adjustment and Inverse FFT Combiner for Multichannel CommunicationNetwork, include transceivers which are capable of polling all of thechannels available to the system, to detect signal activity on therespective channels. These transceivers are also capable of transmittingor receiving signals essentially simultaneously over any or all of thechannels. Basically, each of the station 14 includes a transceiver thathas, for processing received signals, a wideband Discrete FourierTransform channelizer and a plurality of filters and digital signalprocessors for reproducing from received communications signals digitalsignals that represent communications over the individual channels. Thetransceiver also includes, for transmitting signals, a second pluralityOf digital signal processors and an inverse Discrete Fourier Transformcombiner that together produce a combined signal that represents theplurality the individual channel signals, and a multi channeltransmitter that transmits an associate multiple frequency communicationsignal. Each base station 14 maintains an internal table 15, listing thechannels allocated to the station by the controller and processes thecommunications signals that it receives and transmits in accordance withthe allocated channels.

Referring now also to FIG. 2, the cluster controller 12 maintains a loadstatistics table 13 which lists for each of the channels availablethrough the controller, the base station 14 to which the channel isallocated and the current status of the channel, that is, whether thechannel is then assigned to a terminal, i.e., in use, or is then freeover the entire system 10. The controller determines the current statusof the channels using information forwarded to it by the base stations.Each station sends a report to the controller every time it assigns achannel to a terminal and every time it releases, or frees, a channel.

When the cluster controller 12 is powered up, it allocates the channelsamong the base stations 14 according to a default scheme, such as auniform distribution. Thereafter, the cluster controller 12 dynamicallyre-allocates the channels among the base stations, depending on thecurrent demand for channels; the expected demand for channels; or both.

In a first embodiment of the system 10, the controller 12 dynamicallyallocates the channels to the wideband base stations 14 in response torequests for additional channels from the individual base stations. Itthus allocates the channels based on current demand. A base stationissues a request whenever it lacks an available channel to assign to aterminal 18 that requires service.

Referring now also to FIGS. 3A-3B, when a base station 14 determines itrequires another channel it surveys its environment by polling thesystem channels to determine signal activity on each of the channels(steps 20-22). The base station makes a list of the channels determinedto be inactive because of the lack of signal activity and sends thislist to the controller as part of a request for an additional channel(step 24).

The cluster controller uses the list to enter its load statistics table13. From this table the cluster controller determines if a first channelon the list is free (step 26). If this channel is free, the clustercontroller allocates the channel to the requesting base station (steps28 and 30). If this channel is in use, the cluster controller determinesif a next channel on the list is free, and so forth, until it eitherfinds a free channel or it checks every channel on the list. (steps32-34).

If the cluster controller has checked all the channels on the list, thecluster controller then re-uses one of these channels, that is, itallocates the channel to the requesting base station without removing itfrom the station to which it is currently allocated (step 35) FIG. 4A.Since the requesting base station did not detect signal activity on thechannel, communications over this channel within in its cell site shouldbe undetectable at the other base station utilizing the same channel.Accordingly, the controller 12 need not separately determine if there-use will cause interference, even if the cell sites to which thechannel is to be simultaneously assigned are contiguous. The controllercan thus take advantage of channel re-use, without requiring studies ofthe terrain, as is required in prior known systems.

Referring now to FIGS. 4A-4B, in an alternative mode of operation thebase station 14 polls the channels only until it finds an inactivechannel (step 36). It then identifies only this channel in its requestfor an additional channel (step 38). The controller responds to thisrequest by consulting the load statistics table 13 and determining ifthe channel is free (step 40). If so, the controller allocates thechannel to the requesting base station (steps 42 and 44). If not, thecontroller requests that the base station continue polling the channelsto find a next inactive channel, and so forth, until a channel isallocated to the requesting base station or all channels have beenpolled (steps 45-47). The controller may re-use a channel, as necessary(step 48).

Referring to FIG. 5, in a second embodiment of the system, thecontroller 12 includes in its load statistics table 13' informationrelating to the rates at which the base stations assign channels to theterminals. It thus accumulates the information forwarded to it by thebase stations, determines how many times each base station assignschannels over a predetermined period of time and the number of thesechannels that are simultaneously in use over the predetermined timeperiod. The controller then determines a channel usage rate for each ofthe base stations based on this accumulated information. If the rate fora particular base station is above a predetermined maximum value, itindicates that the base station requires all the channels allocated toit to handle current demand. Accordingly, the controller will not removea channel from this base station.

Referring also to FIG. 6, when the controller receives a request for anadditional channel from a base station, it first determines if anychannels specified therein are free by executing the operationsnecessary to perform the steps 26-28 of FIGS. 3A-3B, Once a free channelis determined, the controller checks the channel usage rate associatedwith the base station to which the channel is allocated. If the rate isbelow the predetermine maximum, the controller allocates the channelfrom the current base station to the requesting base station (steps50-54). If the rate exceeds the predetermined maximum, the controllerdetermines that the channel cannot be reallocated (step 56). Thecontroller then determines if a next channel on the list can bereallocated, and so forth (step 57). As appropriate, the channel can bere-used as described above.

The cluster controller, using either of these modes of operation,dynamically allocates channels to the base stations, within one or twoseconds of receiving a request from a base station, taking only as longas it takes to enter the load statistics table using the list providedin the request by the base station. Accordingly, the base station can,without delay, service a terminal, using a newly re-allocated channel.

Referring to FIG. 7, in a third embodiment of the invention, the clustercontroller accumulates in its load statistics table 13" informationrelating to the channel usage of each of the base stations over a numberof predetermined time periods, for example, over weeks, days, hours andso forth. Using this accumulated information, the controller determinespatterns of use and preallocates the channels among the base stations 14at selected times, so that stations with expected high demand forchannels have allocated to them at the appropriate time more channelsthan the stations which have at this same time expected low demand.

If, for example, the controller accumulates the channel usageinformation on a daily basis, it may determine that certain basestations have high demand during the week and others havecorrespondingly low demand during the week. The controller can thuspreallocate more channels to these high demand base stations and fewerchannels to these low demand base stations at the start of each week.Similarly, if the controller maintains information on the hourly usageof the channels, the controller may determine that certain base stationsin the suburbs experience high demand during rush hours and low demandotherwise. The controller can then preallocate more channels to thesebase stations during rush hours and re-allocate channels from themduring other hours.

Referring to FIG. 8, the cluster controller determines, from itsaccumulated channel usage information, patterns of use and the timeperiod over which the usage predictably changes at particular basestations (steps 60-62). It then designates times for preallocatingchannels among the base stations in accordance with these patterns. Ateach of the designated times, the controller preallocates, to the basestations that are then expected to have high demand, free channels thatare currently allocated to the base stations that are then expected tohave low demand. At the same times, the controller removes thesechannels from the low-demand stations (steps 64-66). The controlleravoids preallocating to base stations channels that may causeinterference, for example, channels that are uses by a PCS in the area.Also, it does not re-use channels between contiguous base stations.

Referring now to FIG. 9, the base stations may request additionalchannels from the controller, as needed to handle unexpectedly highdemand. For example, base stations located near a convention site mayrequest additional channels to handle convention traffic. These basestations thus perform the operations described above with reference tosteps 20-24 of FIG. 3A. In response to a request, the controller entersits load statistics table 13", using the channel information in therequest and determines if a first channel on the list is free, asdescribed above with reference to step 26 of FIG. 3A. If so, thecontroller determines if the associated channel usage rate exceeds thepredetermined maximum rate, as described above with reference to step 50of FIG. 6. If it does, the controller determines that this channel cannot be reallocated to the requesting base station (steps 52 and 56 ofFIG. 6). It then reenters the table and checks the availability of anext channel of the list, and so forth, until it determines that aparticular channel is both free and not required to handle the currentdemand at the base station to which it is then allocated (steps 52-54 ofFIG. 6).

The controller then examines the accumulated use statistics for the basestation to which the channel is allocated, to determine if this basestation is expected to experience high demand within the current timeperiod, and thus, is expected to have a need for the channel (step 68),FIG. 9. If the base station is in a period of expected low demand, thecontroller allocates the channel to the requesting base station (step70). If the base station is in a period of expected high demand, thecontroller instead determines that this channel should not bere-allocated and it again re-enters the table. The controller searchesfor another channel on the list that is free and that is assigned to abase station that is associated with a low current channel usage rateand is expected to have low demand (step 72).

If none of the free channels are assigned to base stations with expectedlow demand, the controller must determine, based on the priorities ofthe service provider, whether or not to remove a free channel from abase station that is expected to experience high demand.

Considering again the example of the city convention center, the basestations covering the center request additional channels in the evening,when demand in the city is expected to be low. The controller hasalready preallocated channels to the suburban base stations, inanticipation of the expected high demand. The controller must nowdetermine if it should handle the convention calls by re-allocatingchannels to the city base stations and away from the base stations inthe suburbs that are servicing its regular customers and which areexperiencing their expected high demand. To do so would remove thechannels from the areas then populated by its regular subscribers.

If the service provider places a high priority on having channelsavailable for its regular subscribers, the controller will notreallocate channels from the suburban base stations to theconvention-area base stations. If, however, the service provider has asits priority maximizing profits, the controller will reallocate as manychannels as possible to the convention-area base stations, since themajority of these calls will be made on a high cost roaming basis byout-of-town convention goers.

The foregoing description has been limited to specific embodiments ofthis invention. It will be apparent, however, that variations andmodifications may be made to the invention, with the attainment of someor all of its advantages. Therefore, it is the object of the appendedclaims to cover all such variations and modifications as come within thetrue spirit and scope of the invention.

What is claimed is:
 1. A wireless communication system including:A. aplurality of wideband base stations that service mobile telephoneterminals over a plurality of channels within an assigned frequencyrange, each base station polling the channels within the assignedfrequency range to determine inactive channels and requesting theallocation to the base station of one of the inactive channels: B. acontroller for controlling channel allocation among the base stations,the controller accumulating channel use information from the basestations and allocating the channels among the base stations byallocating to a particular base station one of the channels that thebase station determined to be inactive; and wherein the base stationsinclude in the requests to the controller a list of inactive channels.2. The wireless communication system of claim 1 wherein:a. each basestation notifies the controller when the base station assigns one of thechannels to one of the terminals and when the base station releases thechannel from the terminal; and b. the controller maintains a loadstatistics table indicating the status of each channel.
 3. The wirelesscommunication system of claim 2 wherein the controller consults thetable to determine if a particular channel, which is listed in therequest from the base station, is free over the system.
 4. The wirelesscommunication system of claim 2 wherein the controller accumulates thechannel use information over a number of predetermined time periods anddetermines for each base station a channel usage rate at which the basestation assigns channels to the terminals, the controller allocating achannel from a base station to which the channel is currently assignedto a requesting a base station if the channel usage rate associated withthe base station to which the channel is currently assigned is below apredetermined value.
 5. The wireless communication system of claim 4wherein the controller accumulates information for each base stationrelating to the number of channels in use simultaneously and includesthese numbers in calculation of the channel usage rates for the basestations.
 6. The wireless communication system of claim 5 wherein thecontroller determines from the accumulated channel use information foreach base station an expected channel use, the controller allocating achannel from a current base station to a requesting base station if theexpected channel use associated with the current base station during thecurrent time period is low.
 7. The wireless communication system ofclaim 1 wherein the channel allocated to a particular base station isone that the controller determines is not in use at any other basestation.
 8. A method of dynamically allocating channels among aplurality of wideband base stations including the steps of:A.maintaining a table of channels in a controller; B. determining from thebase stations the current status of channels and including in the tableof channels an indication for each channel that the channel is either inuse or free; C. requiring a base station requesting a channel allocationto include in the request a list of channels determined by the basestation to be inactive; D. determining the current status of a firstchannel on the list; E. allocating the channel to the requesting basestation.
 9. The method of claim 8 wherein:E11. the step of allocatingthe channel to the requesting base station is performed if the channelis free; and further comprising the steps: F. otherwise determining if anext channel on the list is free and if so allocating the channel to therequesting base station; and G. repeating step F until either a channelis allocated or the status of every channel on the list has beenchecked.
 10. A method of dynamically allocating channels among aplurality of wideband base stations including the steps of:A.maintaining a table of channels in a controller: B. determining from thebase stations the current status of channels and including in the tableof channels an indication for each channel that the channel is either inuse or free; C. accumulating channel status information and determiningfor each base station a channel usage rate which indicates the number oftimes the base station assigns channels to terminals over apredetermined time period; D. requiring a base station requesting achannel allocation to include in the request a list of channelsdetermined by the base station to be inactive; E. determining thecurrent status of a first channel on the list; F. determining if thechannel usage rate associated with the base station to which the channelis allocated is below a predetermined value; G. re-allocating thechannel to the requesting base station if the associated channel usagerate is below the predetermined value; H. otherwise, determining if thechannel usage rate associated with a next channel on the list is belowthe predetermined value; I. repeating steps G and H until either achannel is allocated or every channel on the list has been checked. 11.The method of claim 10 wherein the step of determining the channel usagerate includes determining the number of channels in use simultaneouslyover the predetermined period of time and using the number indetermining the channel usage rate.
 12. The method of claim 10wherein:F1. the step of determining if the channel usage rate associatedwith the base station to which the channel is allocated is below apredetermined value is performed if the channel is free; and H1. thestep of determining if the channel usage rate associated with a nextchannel on the list is below the predetermined value is performed if thenext channel on the list is free.
 13. A method of dynamically allocatingchannels among a plurality of wideband base stations including the stepsof:A. maintaining a table of channels in a controller; B. determiningfrom the base stations the current status of channels and including inthe table of channels an indication for each channel that the channel iseither in use or free; C. accumulating channel status information anddetermining for each base station a channel usage rate at which the basestation assigns the channels allocated to the base station to mobiletelephone terminals; D. requiring a base station requesting a channelallocation to include in the request a list of channels determined bythe base station to be inactive; E. determining the current status of afirst channel on the list; F. determining if the channel usage rateassociated with the base station to which the channel is currentlyallocated is below a predetermined value; G. allocating the channel tothe requesting base station if the associated channel usage rate isbelow the predetermined value; H. otherwise, determining if the channelusage rate associated with the base station to which a next channel onthe list is allocated is below the predetermined value; and I. repeatingsteps G and H until either a channel is allocated or the status of everychannel on the list has been checked.
 14. The method of claim 13wherein:a. the step of determining the channel usage rate for the basestation includes determining an expected channel usage rate over apredetermined time period; and b. the step of determining if the channelusage rate is below the predetermined value includes determining if theexpected rate is below the predetermined value.
 15. The method of claim14 further including the step of preallocating channels among the basestations at predetermined times based on the expected rate of channelusage, a number of the channels currently allocated to base stationshaving low expected channel usage rates being reallocated to basestations having high expected channel usage rates.
 16. The method ofclaim 13 wherein:F1. the step of determining if the channel usage rateassociated with the base station to which the channel is currentlyallocated is below a predetermined value is performed if the channel isfree; and H1. the step of determining if the channel usage rateassociated with the base station to which a next channel on the list isallocated is below the predetermined value is performed if the nextchannel on the list is free.
 17. A method of dynamically allocatingchannels among a plurality of wideband base stations including the stepsof:A. maintaining a table of channels in a controller; B. determiningfrom the base stations the current status of channels and including inthe table of channels an indication for each channel that the channel iseither in use or free; C. accumulating channel status information anddetermining for each base station a channel usage rate at which the basestation assigns the channels allocated to the base station to mobiletelephone terminals; D. determining patterns of use over all the basestations; E. preallocating channels among the base stations based on thepatterns of use; F. designating times at which the patterns of usechange and pre-allocating channels at the designated times; and furtherincluding the step of, for each base station:a. determining the numberof channels in use simultaneously over a predetermined period of time;b. determining over the predetermined time period the number of channelsassigned to the terminals; and c. determining a channel usage rate basedon the results of steps a and b; wherein if the channel usage rate isabove a predetermined value the channel is not re-allocated from thebase station to which the channel is currently allocated.
 18. The methodof claim 17 further including the steps ofF. requiring a base stationrequesting a channel allocation to include in the request a list ofchannels determined by the base station to be inactive; G. determiningthe current status of a first channel on the list; H. determining if thechannel usage rate associated with the base station to which the channelis currently allocated is below the predetermined value; I. allocatingthe channel to the requesting base station if the associated channelusage rate is below the predetermined value; J. otherwise, determiningif the channel usage rate associated with the base station to which anext channel on the list is allocated is below the predetermined value;and K. repeating steps I and J until either a channel is allocated orthe status of every channel on the list has been checked.
 19. The methodof claim 18 wherein:H1. the step of determining if the channel usagerate associated with the base station to which the channel is currentlyallocated is below the predetermined value is performed if the channelis free; and J1. the step of determining if the channel usage rateassociated with the base station to which a next channel on the list isallocated is below the predetermined value is performed if the nextchannel on the list is free.